Method of making grinding members

ABSTRACT

A method of making a grinding member comprising a composition of a hardened resin and abrasive particles on a base, in which the resin in a kneadable condition is rolled on the base with a master roller to a predetermined profile and the resin is thereafter caused to harden slowly substantially without change of shape or volume, wherein there is included the improvement of initially filling the resin with a particulate substance imparting at least one of thermal and electrical conductivity, heat-, shock- and wear-resistance and ready wearability, of initially filling the resin with coarse abrasive particles and subsequently embedding fine abrasive particles in its exposed surface, and/or of bonding abrasive particles to the profiled surface by means of a hardenable resin the same as or compatible with that of the composition.

[ Nov. 6, 1973 METHOD OF MAKING GRINDING MEMBERS [75] Inventor: IRaymond Thomas Hallewell,

Hillingdon Heath, Middlesex, England [73] Assignee: Toolmasters Limited,Hillingdon Heath, Middlesex, England 22] Filed: Jan. 6, 1969 21 Appl.No.: 789,360

Related US. Application Data [63] Continuation-impart of Ser. No.695,56l, Jan. 4,

-'l968, Pat. No 3,551,125.

[30] Foreign Application Priority Data Jan. 4, 1968 Great Britain 717/68[52 US. Cl 51/295, 51/293, 51/298 [51] Int. Cl B24b 53/06, B24d 5/00[58] Field of Search 51/293, 295, 298,

[56] References Cited UNITED STATES PATENTS I 3,415,635 12/1968Hallewell 5l/298 3,424,566 l/l969 Kuenstlc et al. 5l/293 PrimaryExaminerDonald J. Arnold Attorney-Woodhams, Blanchard and Flynn [57]ABSTRACT A method of making a grinding member comprising a compositionof a hardened resin and abrasive particles on a base, in which the resinin a kneadable condition is rolled on the base with a master roller to apredetermined profile and the resin is thereafter caused to hardenslowly substantially without change of shape or volume, wherein there isincluded the improvement of initially filling the resin with aparticulate substance imparting at least one of thermal and electricalconductivity, heat-, shockand wear-resistance and ready wearability, ofinitially filling the resin with coarse abrasive particles andsubsequently embedding fine abrasive particles in its exposed surface,and/or of bonding abrasive particles to the profiled surface by means ofa hardenable resin the same as or compatible with that of thecomposition.

20 Claims, No Drawings Characteristic'of hardened composition 1 METHODMAKING GRINDING MEMBERS CROSS-REFERENCE TO RELATED APPLICATION Thisapplication is a continuation-in-part of my copending application Ser.No. 695 561, filed Jan. 4, 1968, now U.S. Pat. No. 3 551 125.

This invention relates to the production of grinding members and is amodification or improvement of that described and claimed in BritishPatent Specification No. 1,044,784.

According to the present invention there is provided a method of makinga grinding member having a profiled grinding surface comprising-forminga body of a kneadable composition comprising a hardenable systheticresin having a filler dispersed therethrough and having abrasiveembedded in an exposed surface thereof, rolling the said exposed surfaceto the required predetermined profile with a master roller whilst thecomposition is still in a plastic state, and thereafter causing the bodyto harden with substantially no vol-- ume change.

Theinvention also provides a method of making a grinding member having aprofiled grinding surface comprising forming a body of a kneadablecomposition cornprising a hardenable synthetic resin having a fillerdispersed therethrough, and, whilst the. composition is still in aplastic state, embedding abrasive in an exposed ferent materials, butthe abrasive may in'some cases also be the tiller or dispersed throughthe composition with a different filler.

The filler imparts bulk to the composition, aids in the H production ofthe required kneadable consistency for rolling, and imparts strength andrigidity to the hardened product. Any one or more of a wide variety offillers may be employed according to the physical properties required ofthe product.

' Variouscomrninuted 'ifiiars'cas for example be em ployed as fillers.Hard metals such as steel give a product which retains its accuracy ofprofile over long periods, whereas softer metals such as copper oraluminium have the advantage of wearing in use to continually exposefresh abrasive; these softer metals, giving a soft wearing bond, areemployed for fine work or for fast removal of stock without risk ofdamage to the work.

The following Table illustrates properties typically required ofgrinding wheels for particular purposes together with examples ofappropriate'fillers for use in the method according to the invention.

Advantage or suited use of grinding member Examples of appropriatefillers Soft wearing bond Shock resistance working wheels.

minimumwheel wear where high resilience is required in hard (a) for finework Soft metals such as copper or aluminium; soft non- (b) for faststock removal without damage metals such asvwood flour, chalk powder,marble flour. slate powder; silica flouryhardmetals such as steels.

aluminium oxide, silicon carbide. nylon; asbestos powder.

Electrical conductivity for electrolytic grinding..... electricallyconductive metals such as copper and aluminium; electrically conductivenonmetals such as graphite; nonmetals and plastics materials coated withelectrically conductive metal. Thermal conductivity minimum damage towork through local thermally conductive metals such as copper oroverheating during grinding. aluminium. Heat-resistant bond minimumdamage to wheel due to local overheat-resistant materials such as micaor asbestos heating during grinding.

powder.

surface of the body and rolling the said exptiaasnnai' to apredetermined profile with a master roller, the body thereafter beingcaused to harden with substantially no volume change. The abrasive maybe appli'ed superficially to the composition before or after rolling asaseparate step, or simultaneously with rolling in, a

single operation.

For the production of a grinding wheel, a layer of the composition maybe applied around the rim of a supporting disc and then treated asdescribed above. The rim of the disc may be pro-formed to the requiredprofile before the application of the composition, but is preferablyflat and roughened, as by scoring or pitting, to provide a key for thekneadable composition.

Due to the workable nature of the plastic composi-j tion, the method ofthe invention does not require the D The fillers mentioned above can beused alone, .but

where a combination of properties is required of the finishing grindingmember a mixture ofdiffer'ent fillers may be employed. Theparticular-filler 'or fillers used, and the proportion or proportionsthereof employed, is selected according'to the use to which the grindingmember is to be put.

Where a comminuted metal or mixture of metals is employed alone as thetiller, the metallic component will normally constitute a majorproportion by weight of the kneadable composition, but where a mixtureof metal with another filler (e.g., an abrasive such as diamond, aluminaor silicon carbide, or a filler imparting shock-or heat resistance) isemployed, the metallic component may constitute only a minor proportionby weight of the composition.

j As indicated above the total proportion of filler employed in thecomposition may vary over a wide range according to the intended purposeof the product. In general however, the volume proportions will rangefrom 60 percent filler, 40 percent resin where no abrasive is includedto 60 percent resin, 40 percent filler where abrasive is present.

The identity, amount, and grain size of the abrasive applied to theexposed surface of the grinding wheel will also be chosen according tothe intended use of the finished grinding member, as is well understoodin the art. For example diamond used as the applied abrasive willnormally be of from 80 to 200 grit size, the finer particles being usedfor accurate work and the coarser for rough grinding.

The kneadable composition may include abrasive particles as or inaddition to the filler. If this abrasive is relatively coarse, andabrasive of finer grit size is applied superficially to the composition,a grinding member is obtained which initially (when the profile is mostaccurate) is suited for finish grinding; as the profile wears thecoarser abrasive is exposed and the member can then be used for roughgrinding.

In one embodiment of the method according to the invention the exposedsurface of the composition is first rolled to the required profile and.then has applied thereover an unfilled liquid resin adhesive which isthe same as or compatible with the resin of the base composition; theabrasive particles are then applied to the adhesive which holds themuntil they are rolled in. The composition and resin adhesive are thenhardened togetherto give a unified product. The use of adhesive in thismanner ensures that the individual abrasive grains are intimatelysurrounded by hardened resin. Alternatively the resin adhesive andabrasive may be applied together, e.g., by spraying. in theseembodiments the superficially applied abrasive may be of finer grainsize than a coarser abrasive dispersed through the composition asdescribed above.

Where a comminuted metal is employed as filler for the resin it willnormally constitute a major proportion by weight of the kneadablecomposition, but this is not essential, especially where other fillersare also incor- For superficial application, the abrasive particles maybe simply sprinkled onto the surface of the composition, but arepreferably sprayed on, e.g., in an air jet.

7 In the production of a grinding wheel the abrasive may for example besprayed onto the peripheral layer from a spray head which,for'app'lication during or after profiling, is most advantageouslymounted in place of the usual forming tool on a standard wheel-formingapparatus such as the Diaform equipment described in British PatentSpecification No. 573,877.

The advantage of mounting the spray jet on a Diaform is that the jet iskept ata constant distance from the face of the wheel; this isimportant, as any variation in this distance will vary the concentrationof the abrasive applied, due to spread as the abrasive leaves the jet.

With the spray method using a predetermined pressure and distance, thepenetration and concentration of abrasive applied to the wheel can becontrolled; in the case of simultaneous impregnation and profiling thepenetration need only be deep enough to key the abrasive, as it will beimmediately rolled into position.

Simultaneous forming and impregnation with abrasive is advantageous,because the optimum consistency of the hardening composition for boththe rolling and the impregnation steps is the same; if application ofabrasive is delayed until the composition has hardened further, theabrasive may be loosely bonded and more likely to out of the wheelduring grinding.

The plastic composition should be of such consistency for the profilingand impregnating step that it does not stick to the roller. The resinand hardening agent used in the composition are therefore preferably soselected that the prepared composition retains its workable consistencyfor an extended period, e.g., for an hour or more.

To obtain the optimum workable consistency it may be necessary toinclude a thickening agent, such as silica, in the composition.Polymerisable epoxy or polyester resins, in admixture with a hardeningagent e. g., one comprising a polyamide and a mild base such as anamine, are suitable for use as the resinous component of the compositionand as the liquid resin adhesive where one is used. Acrylic resins withappropriate j hardening agents are also suitable for these purposes.

As indicated above abrasive particles may be employed as the filler, oras part of the filler, and this permits wheels to be produced havinglayers with abrasives of different grain size. For example the kneadablecomposition may be wholly or partially filled with abrasive ofrelatively coarse grain size, a finer abrasive (which may be the same asor different from the coarse abrasive) being applied, superficiallyduring profiling. Initially, whenthe form of this wheel is mostaccurate, fine grit is exposed and the wheel can hence be used forfinish grinding; as the form wears, coarse abrasive is exposed renderingthe wheel more suited for rough grindmg.

Embodiments of the invention are illustrated by the following specificexamples.

EXAMPLE 1 thick and having a roughened rim is mounted on the spindle ofa grinding machine. A thin layer of Devcon A" (Trade Mark) a resinouscomposition including 80 percent by weight comminuted steel and 20percent by weight curable epoxy resin, is applied around the rim of thedisc and allowed to partially harden. The required form is then rolledinto the peripheral layer of Devcon A by means of a master roller,whilst diamond dust is sprayed onto the layer immediately ahead of theroller from a spray head mounted in place of the forming tool on awheel-forming apparatus. The profiled and impregnated layer of Devcon Ais then allowed to set to its final hardness. The Devcon A" sets to ahard'mass with substantially no shrinkage, so that a hard-wearingabrasive surface of accurate profile is obtained.

EXAMPLE 2 EXAMPLE 3 The procedure of Example 1 was repeated using as thekneadable composition a curable epoxy resin con- A metal disc of about 6inches diameter, about 1 inch taining 80 wt. percent of copper asfiller. An electri-, cally conductive wheel of accurate profile,suitable'for electrolytic grinding was obtained.

EXAMP E 4 The procedure of Example 1 was repeated employing a kneadablecomposition containing 15 wt. percent epoxy resin, 40 wt. percentcomminuted aluminium and 45 wt. percent 80 grit size diamond dust, thediamond dust applied superficially being of 200 grit size. The wheelobtained was a relatively soft-wearing thermally conductive wheel havingan accurate profile with fine abrasive exposed. The wheel is initiallysuited for fine work, but as it wears coarser abrasive is exposed forrough grinding with fast stock removal.

EXAMPLE 5 The procedure of Example 1 was repeated using a composition inwhich 40 wt. percent of the steel was replaced by granulated nylon, ahard-wearing shockresistant wheel beingobtained.

ExAMrLE 6 The procedure of Example I was repeated using a kneadablecomposition of a curable polyester resin containing as filler 60 percentby volume of a 50/50 mixture of wood flour and marble flour, a verysoftwearing wheel for fast stock removal being obtained.

EXAMPLE 7 The procedure of Example 1 was repeated using a kneadablecomposition of a curable polyester resin containing as filler 30 percentby volume of asbestos powder and 30 percent by volume of siliconcarbide, the wheel obtained being very hard, wear-resistant,

shock-resistant and heat-resistant.

' ExAiLiiLEs A wheel for electrolytic grinding was produced by repeatingthe procedure of Example 3 using as filler 55 percent by'volume ofgraphite powder in place of the copper.

EXAMPLE 9 A steel disc of the dimensions specified in Example 1 ismounted on the spindle of a grinding machine, and a layer of thekneadable composition used in Example 4 is applied around its roughenedrim and then rolled to the required profile with a master roller. A thincoating of the curable epoxy resin, without a filler and in liquid form,is applied over the profiled surface, and diamond dust of 200 grit sizeis dusted uniformly over this adhesive layer and is rolled in with thesame master roller after permitting the adhesive to set partially. The

composition and resin adhesive then set together to their final hardnessto yield an integral wheel initially suited for fine work but whichwears in use to expose coarser abrasive for rough grinding. Theprocedure of this Example is equally applicable to the compositionsemployed in Example 1 to 3 and 5 to 8.

EXAMPLE 10 The procedure of Example 9 was repeated employing a kneadablecomposition containing 50 percent by volume of curable epoxy resin and50 percent by volume of a 60/40 mixture of slate powder and silicaflour. A hard-wearing wheel with firmly bonded abrasive was obtained.

EXAMPLE 1 l The procedure of Example 10 was repeated except that nolayer of liquid resin adhesive was employed, the diamond dust beingapplied directly to the profiled surface and then rolled in. Ahard-wearing wheel, but with the abrasive somewhat less firmly bonded,was obtained.

' EXAMPLE 12 The procedure of Example 1 l was repeated using thekneadable composition specified in Example 6, a softwearing wheel beingobtained.

EXAMPLE 13 Example 4 was repeated except that the kneadable compositionwas profiled without the superficial application of fine abrasive. Athermally conductive softwearing wheel was obtained suitable for rapidrough grinding.

EXAMPLE 14 The procedure of Examples 11 and 12 was repeated employingthe kneadable compositions used in Examples 1-3, 5, and 7-10.

' What is claimed is:

I l. in a method of making a grinding member having I V abrasiveparticles embedded in a substrate, said substrate comprising a filledresin consisting essentially of a synthetic'resin containing a hardenerfor curing said resin without application of heat, said resin havingparticulate inert filler dispersed therethrough, the improve'ment whichcomprises the steps of:

l. placing a continuous layer of said filled resin on a base,

3. applying to said profiled surface abrasive particles and a liquidadhesive resin which adheres to said filled resin and said abrasiveparticles,

4. causing the filled resin and the adhesive resin to harden slowlywithout changing the shape of the surface and with substantially novolume change to form a grinding member having a grinding surface ofsaid final profile and to unite the filled resin layer to the base andto the abrasive particles.

2. A method as defined in claim 1 wherein said adhesive resin andabrasive particles are applied to said profiled surface in admixture.

3. A method as defined in claim 1 wherein said liquid adhesive resin isapplied alone over said profiled surface and said abrasive particles arethereafter embedded in said adhesive resin coating.

4. A method as defined in claim 1 wherein said adhesive resin is thesame as said resin of said layer.

5. A method as defined in claim 1 wherein said filler comprises coarseabrasive particles and wherein said abrasive particles subsequentlyapplied to said profiled surface are fine abrasive particles.

6. A method as defined in claim 1 wherein said filler imparts to saidresin layer at least one of the properties of thermal conductivity,electrical conductivity, heat resistance, shock resistance and wearresistance.

7. A method as defined in claim 1 wherein said filler is selected fromthe group consisting of wood flour, chalk powder, marble flour, slatepowder, silica flour, aluminum oxide, silicon carbide, diamond dust,nylon, asbestos powder, mica powder, graphite, comminuted metals,metal-coated particles, and mixtures thereof.

8. A method as defined in claim 1, wherein the base comprises a centralsupporting disc and the continuous resin layer is of an annularconfiguration disposed around the rim of the disc with the exposedsurface of the layer constituting the peripheral surface of the annularlayer.

9. A method as defined in claim 1, wherein the base comprises a centralsupporting disc and the continuous resin layer is of an annularconfiguration disposed around the rim of the disc, and wherein theexposed surface of the layer is rolled to said final profile while saiddisk is mounted in its operable grinding position, whereby the grindingmember is produced already mounted and trued up in position ready foruse.

10. A method of making a grinding member having abrasive particlesembedded in a synthetic resin substrate, the method comprising the stepsof:

1. providing a hardenable synthetic resin containing a hardene forcuring said resin without application of heat,

2. mixing said resin with coarse abrasive particles so that said coarseabrasive particles become dispersed in said resin,

3. placing a continuous layer of said resin/abrasive mixture on a base,

4. while the resin is supported on the base and is in a partiallyhardened condition in which it is capable of being permanently deformedupon application of pressure thereto and is nonsticky,

a. molding the resin layer to alter the shape of said resin layer bymoving a rotating shaping roller over an exposed surface of the resinlayer and applying a deforming pressure onto said surface of said resinlayer by means of the roller and thereby altering the shape of saidresin layer until it has been deformed to a final profile,

b. applying fine abrasive particles to said exposed surface of saidlayer,

5. causing the resin to harden slowly without changing the shape of thesurface and with substantially no volume change to form a grindingmember having a grinding surface of said final profile and to unite theresin layer to the base and to the fine abrasive particles.

ll 1. A method as defined in claim 10 wherein said fine abrasiveparticles are embedded in said exposed surface after it has beendeformed to said final profile.

12. In a method of making a grinding member having abrasive particlesembedded in a synthetic resin substrate, the improvement which comprisesthe steps of;

1. providing a hardenable synthetic resin containing a hardener forcuring said resin without application of heat,

2. dispersing particles of inert filler material in said resin,

3. placing a continuous layer of said filled resin on a base,

4. while the filled resin is supported on the base and is in a partiallyhardened condition in which it is capable of being permanently deformedupon application of pressure thereto and is nonsticky, molding the resinlayer to alter the shape of said resin layer by moving a rotatingshaping roller over an exposed surface of the resin layer and applying adeforming pressure onto said surface of said resin layer by means of theroller and thereby altering the shape of said resin layer until saidexposed surface thereof has been deformed to a final profile,

5. causing the resin to harden slowly without changing the shape of thesurface and with substantially no volume change to form a grindingmember having a grinding surface of said final profile and to unite theresin to the base, said filler material comprising at least onesubstance imparting to said hardened resin layer at least one of theproperties of thermal conductivity, electrical conductivity, heatresistance, shock resistance, wear resistance and ready wearability.

13. A method as defined in claim 12 wherein the filler material isselected from the group consisting of wood flour, chalk powder, marbleflour, slate powder, silica flour, aluminium oxide, silicon carbide,diamond dust, nylon, asbestos powder, mica powder, graphite, comminutedmetals, metal-coated particles, and mixtures thereof.

14. A method as defined in claim 12, wherein the base comprises acentral supporting disc and the continuous resin layer is of an annularconfiguration disposed around the rim of the disc with the exposedsurface of the layer constituting the peripheral surface of the annularlayer.

115. A method as defined in claim 12, wherein the base comprises acentral supporting disc and the continuous resin layer is of an annularconfiguration disposed around the rim of the disc, and wherein theexposed surface of the layer is rolled to said final profile while saiddisc is mounted in its operable grinding position, whereby the grindingmember is produced already mounted and trued up in position ready foruse.

16. A method as defined in claim 10 wherein the base comprises a centralsupporting disc and the continuous resin layer is of an annularconfiguration disposed around the rim of the disc with the exposedsurface of the layer constituting the peripheral surface of the annularlayer.

17. A method as defined in claim 10, wherein the base comprises acentral supporting disc and the con.- tinuous resin layer is of anannular configuration disposed around the rim of the disc, and whereinthe exposed surface of the layer is rolled to said final profile whilesaid disc is mounted in its operable grinding position, whereby thegrinding member is produced already mounted and trued up in positionready for use.

18. A method as defined in claim 1 wherein said abrasive particles aresprayed onto said profiled surface.

19. A method as defined in claim 10 wherein the said fine abrasiveparticles are sprayed onto said exposed surface after it has beenprofiled.

20. A method as defined in claim 12 wherein abrasive particles aresprayed onto said exposed surface of said resin layer after profilingbut before the resin layer has hardened.

2. dispersing particles of inert filler material in said resin, 2.mixing said resin with coarse abrasive particles so that said coarseabrasive particles become dispersed in said resin,
 2. A method asdefined in claim 1 wherein said adhesive resin and abrasive particlesare applied to said profiled surface in admixture.
 2. while the filledresin is supported on the base and is in a partially hardened conditionin which it is capable of being permanently deformed upon application ofpressure thereto and is nonsticky, molding the resin layer to alter theshape of said resin layer by moving a rotating shaping roller over anexposed surface of the resin layer and applying a deforming pressureonto said surface of said resin layer by means of the roller and therebyaltering the shape of said resin layer until said exposed surfacethereof has been deformed to a final profile,
 3. A method as defined inclaim 1 wherein said liquid adhesive resin is applied alone over saidprofiled surface and said abrasive particles are thereafter embedded insaid adhesive resin coating.
 3. applying to said profiled surfaceabrasive particles and a liquid adhesive resin which adheres to saidfilled resin and said abrasive particles,
 3. placing a continuous layerof said resin/abrasive mixture on a base,
 3. placing a continuous layerof said filled resin on a base,
 4. while the filled resin is supportedon the base and is in a partially hardened condition in which it iscapable of being permanently deformed upon application of pressurethereto and is nonsticky, molding the resin layer to alter the shape ofsaid resin layer by moving a rotating shaping roller over an exposedsurface of the resin layer and applying a deforming pressure onto saidsurface of said resin layer by means of the roller and thereby alteringthe shape of said resin layer until said exposed surface thereof hasbeen deformed to a final profile,
 4. while the resin is supported on thebase and is in a partially hardened condition in which it is capable ofbeing permanently deformed upon application of pressure thereto and isnonsticky, a. molding the resin layer to alter the shape of said resinlayer by moving a rotating shaping roller over an exposed surface of theresin layer and applying a deforming pressure onto said surface of saidresin layer by means of the roller and thereby altering the shape ofsaid resin layer until it has been deformed to a final profile, b.applying fine abrasive particles to said exposed surface of said layer,4. causing the filled resin and the adhesive resin to harden slowlywithout changing the shape of the surface and with substantially novolume change to form a grinding member having a grinding surface ofsaid final profile and to unite the filled resin layer to the base andto the abrasive particles.
 4. A method as defined in claim 1 whereinsaid adhesive resin is the same as said resin of said layer.
 5. A methodas defined in claim 1 wherein said filler comprises coarse abrasiveparticles and wherein said abrasive particles subsequently applied tosaid profiled surface are fine abrasive particles.
 5. causing the resinto harden slowly without changing the shape of the surface and withsubstantially no volume change to form a grinding member having agrinding surface of said final profile and to unite the resin layer tothe base and to the fine abrasive particles.
 5. causing the resin toharden slowly without changing the shape of the surface and withsubstantially no volume change to form a grinding member having agrinding surface of said final profile and to unite the resin to thebase, said filler material comprising at least one substance impartingto said hardened resin layer at least one of the properties of thermalconductivity, electrical conductivity, heat resistance, shockresistance, wear resistance and ready wearability.
 6. A method asdefined in claim 1 wherein said filler imparts to said resin layer atleast one of the properties of thermal conductivity, electricalconductivity, heat resistance, shock resistance and wear resistance. 7.A method as defined in claim 1 wherein said filler is selected from thegroup consisting of wood flour, chalk powder, marble flour, slatepowder, silica flour, aluminum oxide, silicon carbide, diamond dust,nylon, asbestos powder, mica powder, graphite, comminuted metals,metal-coated particles, and mixtures thereof.
 8. A method as defined inclaim 1, wherein the base comprises a central supporting disc and thecontinuous resin layer is of an annular configuration disposed aroundthe rim of the disc with the exposed surface of the layer constitutingthe peripheral surface of the annular layer.
 9. A method as defined inclaim 1, wherein the base comprises a central supporting disc and thecontinuous resin layer is of an annular configuration disposed aroundthe rim of the disc, and wherein the exposed sUrface of the layer isrolled to said final profile while said disk is mounted in its operablegrinding position, whereby the grinding member is produced alreadymounted and trued up in position ready for use.
 10. A method of making agrinding member having abrasive particles embedded in a synthetic resinsubstrate, the method comprising the steps of:
 11. A method as definedin claim 10 wherein said fine abrasive particles are embedded in saidexposed surface after it has been deformed to said final profile.
 12. Ina method of making a grinding member having abrasive particles embeddedin a synthetic resin substrate, the improvement which comprises thesteps of;
 13. A method as defined in claim 12 wherein the fillermaterial is selected from the group consisting of wood flour, chalkpowder, marble flour, slate powder, silica flour, aluminium oxide,silicon carbide, diamond dust, nylon, asbestos powder, mica powder,graphite, comminuted metals, metal-coated particles, and mixturesthereof.
 14. A method as defined in claim 12, wherein the base comprisesa central supporting disc and the continuous resin layer is of anannular configuration disposed around the rim of the disc with theexposed surface of the layer constituting the peripheral surface of theannular layer.
 15. A method as defined in claim 12, wherein the basecomprises a central supporting disc and the continuous resin layer is ofan annular configuration dispOsed around the rim of the disc, andwherein the exposed surface of the layer is rolled to said final profilewhile said disc is mounted in its operable grinding position, wherebythe grinding member is produced already mounted and trued up in positionready for use.
 16. A method as defined in claim 10 wherein the basecomprises a central supporting disc and the continuous resin layer is ofan annular configuration disposed around the rim of the disc with theexposed surface of the layer constituting the peripheral surface of theannular layer.
 17. A method as defined in claim 10, wherein the basecomprises a central supporting disc and the continuous resin layer is ofan annular configuration disposed around the rim of the disc, andwherein the exposed surface of the layer is rolled to said final profilewhile said disc is mounted in its operable grinding position, wherebythe grinding member is produced already mounted and trued up in positionready for use.
 18. A method as defined in claim 1 wherein said abrasiveparticles are sprayed onto said profiled surface.
 19. A method asdefined in claim 10 wherein the said fine abrasive particles are sprayedonto said exposed surface after it has been profiled.
 20. A method asdefined in claim 12 wherein abrasive particles are sprayed onto saidexposed surface of said resin layer after profiling but before the resinlayer has hardened.